A cushion-cut jewel, it weighs 34.65 carats and is one of the finest and largest of its kind.

The historic polished stone can be traced back to the ancient diamond mines of south central India. It was first recorded as part of the collection of the Hyderabad state's royal family during the Mughal Empire of the late 1500s to mid 1600s.

The Hyderabad monarchy offered the piece at auction in 1960 where the diamond fetched a price of 46,000 pounds sterling (approximately $69,588 in today's currency) when French jeweller Van Cleef & Arpels bought it via its London branch.

The gem was subsequently named "The Princie" in honour of the 14-year-old Indian Prince of Baroda who attended a Parisian party held by the firm.

Sotheby's auction house, which sold that particular gem, said pink diamonds of such a size were "off-the-scale rare" and never appeared on the open market. It also claimed pink stones were the most desirable of all the colours. Such a hue is thought to be created by a distortion in the crystal structure which absorbs light differently.